Wind-driven effects on spectral amplitudes and seismic detection
thresholds in a polar glacier setting
Abstract
Temporally variable environmental microseismicity and narrowband signals
are both demonstrated to reduce the detectability of small seismic
events. We investigate the influence of winter wind events on detection
thresholds for a 3-sensor seismic network at the terminus of Taylor
Glacier, Antarctica. As wind speeds increase, we observe higher spectral
amplitudes across the frequency spectrum; however, some frequency bands
are preferentially excited. Surprisingly, these spectral peaks shift
frequencies through time. To determine detection thresholds, we
implement a waveform injection routine wherein we add scaled waveforms
to the datastream, and track changes in the size of the smallest scaled
event that we can reliably detect. We thereby demonstrate a capability
to quantify the size of the smallest detectable event in temporally
variable signal environments. Lastly, we propose a method to forecast
our ability to detect sources of a threshold size in measured noise
conditions.